CN106328780B - The method of light emitting diode substrate epitaxial growth based on AlN templates - Google Patents
The method of light emitting diode substrate epitaxial growth based on AlN templates Download PDFInfo
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- 239000000758 substrate Substances 0.000 title claims abstract description 61
- 238000000034 method Methods 0.000 title claims abstract description 55
- 239000011777 magnesium Substances 0.000 claims abstract description 31
- 229910002704 AlGaN Inorganic materials 0.000 claims abstract description 17
- 229910052749 magnesium Inorganic materials 0.000 claims abstract description 12
- 238000001816 cooling Methods 0.000 claims abstract description 11
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims abstract description 10
- 238000012545 processing Methods 0.000 claims description 8
- 229910052751 metal Inorganic materials 0.000 claims description 5
- 239000002184 metal Substances 0.000 claims description 5
- 238000005229 chemical vapour deposition Methods 0.000 claims description 4
- 238000004519 manufacturing process Methods 0.000 abstract description 6
- 239000010410 layer Substances 0.000 description 149
- XCZXGTMEAKBVPV-UHFFFAOYSA-N trimethylgallium Chemical compound C[Ga](C)C XCZXGTMEAKBVPV-UHFFFAOYSA-N 0.000 description 29
- 239000013078 crystal Substances 0.000 description 12
- JLTRXTDYQLMHGR-UHFFFAOYSA-N trimethylaluminium Chemical compound C[Al](C)C JLTRXTDYQLMHGR-UHFFFAOYSA-N 0.000 description 11
- 235000012431 wafers Nutrition 0.000 description 11
- 229910052594 sapphire Inorganic materials 0.000 description 7
- 239000010980 sapphire Substances 0.000 description 7
- 230000008569 process Effects 0.000 description 6
- IBEFSUTVZWZJEL-UHFFFAOYSA-N trimethylindium Chemical compound C[In](C)C IBEFSUTVZWZJEL-UHFFFAOYSA-N 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 3
- 229910052681 coesite Inorganic materials 0.000 description 3
- 229910052906 cristobalite Inorganic materials 0.000 description 3
- 239000011241 protective layer Substances 0.000 description 3
- 239000000377 silicon dioxide Substances 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- 229910052682 stishovite Inorganic materials 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- 230000007704 transition Effects 0.000 description 3
- 229910052905 tridymite Inorganic materials 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000004590 computer program Methods 0.000 description 2
- 239000002019 doping agent Substances 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 230000001788 irregular Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- RGGPNXQUMRMPRA-UHFFFAOYSA-N triethylgallium Chemical compound CC[Ga](CC)CC RGGPNXQUMRMPRA-UHFFFAOYSA-N 0.000 description 2
- GYHNNYVSQQEPJS-UHFFFAOYSA-N Gallium Chemical compound [Ga] GYHNNYVSQQEPJS-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 239000012159 carrier gas Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000013256 coordination polymer Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 229910052733 gallium Inorganic materials 0.000 description 1
- 230000014509 gene expression Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 description 1
- AMGQUBHHOARCQH-UHFFFAOYSA-N indium;oxotin Chemical compound [In].[Sn]=O AMGQUBHHOARCQH-UHFFFAOYSA-N 0.000 description 1
- 238000004020 luminiscence type Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000012858 packaging process Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000002161 passivation Methods 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 229910000077 silane Inorganic materials 0.000 description 1
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/005—Processes
- H01L33/0062—Processes for devices with an active region comprising only III-V compounds
- H01L33/0066—Processes for devices with an active region comprising only III-V compounds with a substrate not being a III-V compound
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/005—Processes
- H01L33/0062—Processes for devices with an active region comprising only III-V compounds
- H01L33/0075—Processes for devices with an active region comprising only III-V compounds comprising nitride compounds
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
- H01L33/26—Materials of the light emitting region
- H01L33/30—Materials of the light emitting region containing only elements of Group III and Group V of the Periodic Table
- H01L33/32—Materials of the light emitting region containing only elements of Group III and Group V of the Periodic Table containing nitrogen
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- Engineering & Computer Science (AREA)
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- Microelectronics & Electronic Packaging (AREA)
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- Led Devices (AREA)
Abstract
The method that the present invention discloses the light emitting diode substrate epitaxial growth based on AlN templates, including：Handle substrate, growth AlxGa(1‑x)N layers, growth AlyGa(1‑y)N layers, growth SivAlzGa(1‑z‑v)N layers, growth doping Si N-type GaN layer, growth Inx1Ga(1‑x1)N/GaN luminescent layers, wherein x1=0.20 0.25, growing P-type AlGaN layer, growth mix p-type GaN layer, the cooling down of magnesium.The invention enables epitaxial growth simplifications, improve the production efficiency of LED.
Description
Technical Field
The invention relates to the technical field of epitaxial growth of a light-emitting diode substrate, in particular to an AlN template-based epitaxial growth method of the light-emitting diode substrate.
Background
A Light Emitting Diode (LED) is a semiconductor DiodeThe device is a device which can convert electric energy into light energy. The LED product has the advantages of energy conservation, environmental protection, long service life and the like, and is widely popular with people. The current market of LEDs pursues high-brightness LED products, and the conventional LED structure mainly includes: a substrate, a low-temperature buffer layer GaN, a GaN layer not doped with Si, a GaN layer doped with Si, a light-emitting layer, a GaN layer doped with Mg and Al, a GaN layer doped with Mg at high temperature, an Indium Tin Oxide (ITO) layer, and SiO2A protective layer, a P electrode and an N electrode.
In the existing LED epitaxial generation process, an epitaxial layer is grown on a sapphire PSS substrate. However, the epitaxial layer grown on the PSS substrate causes the defect of high density in the epitaxial layer, so that the prepared epitaxial wafer has low wavelength hit rate, light crystal quality of the epitaxial wafer, poor crystal quality of a light-emitting layer, low doping efficiency of a P layer and low mobility of a cavity; the prepared LED has the problems of reduced brightness, reduced lighting effect, reduced reverse voltage, poor antistatic capability and the like.
As shown in fig. 1 and fig. 2, fig. 1 is a schematic flow chart of a conventional LED substrate epitaxial growth method in the prior art; fig. 2 is a schematic structural diagram of a conventional LED fabricated by a method of epitaxial growth of a light emitting diode substrate in the prior art. The traditional LED substrate epitaxial growth method comprises the following steps:
step 101, processing a sapphire substrate: introducing H of 100L/min-130L/min under the hydrogen atmosphere of 1000-1100 DEG C2And treating the sapphire substrate for 5-10 minutes by keeping the pressure of the reaction chamber at 100-300mbar (mbar is a pressure unit).
Step 102, growing a low-temperature buffer layer GaN: cooling to 500-3TMGa of 50-100sccm and H of 100-130L/min2And growing a low-temperature buffer layer GaN with the thickness of 20-40nm on the sapphire substrate.
103, etching the low-temperature buffer layer GaN into an irregular island shape: the temperature is raised to 1000-1100 ℃,keeping the pressure of the reaction cavity at 300-3H of 100L/min-130L/min2And keeping the temperature stable for 300-500s to etch the GaN into irregular island shape.
Step 104, growing an undoped U-shaped GaN layer: raising the temperature to 1000-3200-400sccm TMGa, 100-130L/min H2And continuously growing 2-4 mu m of undoped GaN.
Step 105, growing a first Si-doped N-type GaN layer: keeping the pressure and temperature of the reaction chamber constant, and introducing NH with the flow rate of 30000-3200-400sccm TMGa, 100-130L/min H220-50sccm SiH4Continuously growing a first Si-doped N-type GaN layer with the doping concentration of 5E18-1E19atom/cm and the doping concentration of 3-4 μm3(remark 1E19 represents the power of 19 of 10, i.e. 10∧19, and so on).
Step 106, growing a second Si-doped N-type GaN layer: keeping the pressure and temperature of the reaction chamber constant, and introducing NH with the flow rate of 30000-3200-400sccm TMGa, 100-130L/min H22-10sccm SiH4Continuously growing 200-400nm second Si-doped N-type GaN with the Si doping concentration of 5E17-1E18atom/cm3。
Step 107, growing an N-type GaN layer doped with Si in the light emitting layer: NH with the flow rate of 30000-320-40sccm of TMGa, 100-22-10sccm SiH4Continuously growing an N-type GaN layer doped with Si with the concentration of 1E18-5E18atom/cm and the concentration of 50-100nm3。
Step 108, growing In the light emitting layerxGa（1-x)N/GaN layer: the pressure of the reaction cavity is kept at 300-NH of (2)320-40sccm of TMGa, 1500-2000sccm of TMIn, 100-130L/min of N2Growing In-doped 2.5-3.5nmInxGa(1-x)N (x is 0.20-0.25), emission wavelength 450-; then raising the temperature to 750-850 ℃, keeping the pressure of the reaction chamber at 300-400mbar and introducing NH with the flow rate of 50000-70000sccm320-100sccm of TMGa, 100-2Growing 8-15nmGaN layer; then repeating InxGa(1-x)Growth of N, and then repeating growth of GaN to alternately grow InxGa(1-x)The N/GaN luminescent layer has a control cycle number of 7-15.
Step 109, growing a P-type AlGaN layer: keeping the pressure of the reaction cavity at 200-3TMGa 30-60sccm, H100-130L/min2100 TMAl with 130sccm, 1000 Cp with 1300sccm2Mg, continuously growing a P-type AlGaN layer with the thickness of 50-100nm and the Al doping concentration of 1E20-3E20atom/cm3Mg doping concentration of 1E19-1E20atom/cm3。
Step 110, growing a magnesium-doped P-type GaN layer: keeping the pressure of the reaction cavity at 400-320-100sccm of TMGa, 100-21000-Cp of 3000sccm2Mg, continuously growing a P-type GaN layer doped with magnesium with the concentration of 50-200nm, wherein the Mg doping concentration is 1E19-1E20atom/cm3。
Step 111, cooling and cooling: finally, the temperature is reduced to 650 plus 680 ℃, the temperature is preserved for 20-30min, and then the heating system and the gas supply system are closed, and the furnace is cooled.
As shown in fig. 2, a conventional LED is prepared by using a light emitting diode substrate epitaxial growth method in the prior art, and comprises the following structures from bottom to top: substrate 201, GaN layer 202 as low temperature buffer layer, U-type GaN layer 203, N-type GaN layer 204, N electrode 205, light emitting layer 206 (including GaN layer 261 and In)xGa(1-x)N layer 262), Mg and Al doped P-type AlGaN layer 207, Mg doped P-type GaN layer 208 at high temperature, ITO layer 209, SiO2A protective layer 210 and a P-electrode 211.
Therefore, the problem to be solved in the art is to provide an epitaxial growth method of an LED substrate, which has high wavelength hit rate, good lighting effect, high brightness, low voltage, high reverse voltage and strong antistatic capability.
Disclosure of Invention
In view of the above, the invention provides an AlN template-based method for epitaxial growth of a light emitting diode substrate, which solves the technical problems of low wavelength hit rate, poor light efficiency, low brightness, high voltage, low reverse voltage, and poor antistatic capability of an LED epitaxial wafer in the prior art.
In order to solve the technical problem, the invention provides a method for epitaxial growth of a light emitting diode substrate based on an AlN template, which comprises the following steps: treating substrate and growing AlxGa（1-x)N layer, grown AlyGa（1-y)N layer, grown SivAlzGa(1-z-v)N layer, growing Si-doped N-type GaN layer, growing Inx1Ga(1-x1)An N/GaN light-emitting layer, wherein x1 is 0.20-0.25, a P-type AlGaN layer is grown, a P-type GaN layer doped with magnesium is grown, and the temperature is reduced and cooled; wherein,
growing AlxGa(1-x)An N layer, further:
keeping the pressure of the reaction chamber at 100-3100-130L/min N2Growing 500-800nm Al under the conditions of TMGa 50-100sccm and TMAl 100-200sccmxGa(1-x)N layer (x value range is 0.10-0.15);
growing AlyGa(1-y)An N layer, further:
keeping the pressure of the reaction chamber at 100-3100-130L/min N2100-100 sccm TMGa and 50-100sccm TMAlGrowing 500-800nm Al under the conditionyGa(1-y)N layer (y value range is 0.05-0.10);
growing SivAlzGa(1-z-v)An N layer, further:
keeping the pressure of the reaction chamber at 300-3100-130L/min H2200-300sccm TMGa, 50-100sccm TMAl and 5-10sccm SiH4Under the conditions of (1), 500-800nm Si is grownvAlzGa(1-z-v)N layer (z is 0.03-0.05; v is 0.005-0.01), and Si doping concentration is 5E17-5E18atom/cm3。
Further, wherein the processing the substrate, further comprises:
simultaneously introducing NH with the flow of 10000-20000sccm into the reaction cavity of the metal organic chemical vapor deposition system with the substrate3100-130L/min H2And raising the temperature to 900-1000 ℃, and processing the substrate under the condition that the pressure of the reaction cavity is 100-200 mbar.
Further, wherein, growing the N-type GaN layer doped with Si further comprises: NH3, TMGa and H are introduced2And SiH4And continuously growing the N-type GaN layer doped with Si.
Further, wherein, growing the N-type GaN layer doped with Si further comprises:
keeping the pressure of the reaction chamber at 300-220-50sccm SiH4Continuously growing a Si-doped N-type GaN layer of 3-4 μm with a Si doping concentration of 5E18-1E19atom/cm3。
Further, wherein, growing the N-type GaN layer doped with Si further comprises:
the pressure of the reaction cavity is kept at 600mbar and the temperature is kept at 1200 ℃ under 300℃ and 1000℃ respectivelyNH3 with the flow rate of 30000-220-50sccm SiH4Continuously growing a first Si-doped N-type GaN layer of 3-4 μm with a Si doping concentration of 5E18-1E19atom/cm3；
Keeping the pressure of the reaction chamber at 300-3200-400sccm TMGa, 100-130L/min H22-10sccm SiH4Continuously growing a second Si-doped N-type GaN layer of 200-400nm, wherein the doping concentration of Si is 5E17-1E18atom/cm3。
Further, wherein, growing the N-type GaN layer doped with Si further comprises:
keeping the pressure of the reaction chamber at 300-220-50sccm SiH4Continuously growing a first Si-doped N-type GaN layer of 3-4 μm with a Si doping concentration of 5E18-1E19atom/cm3；
Keeping the pressure of the reaction chamber at 300-3200-400sccm TMGa, 100-130L/min H22-10sccm SiH4Continuously growing a second Si-doped N-type GaN layer of 200-400nm, wherein the doping concentration of Si is 5E17-1E18atom/cm3；
Keeping the pressure of the reaction chamber at 300-320-40sccm of TMGa, 100-22-10sccm SiH4Continuously growing a third Si-doped N-type GaN layer with the Si doping concentration of 1E18-5E18atom/cm at 50-100nm3。
Further, therein, In is grownx1Ga(1-x1)An N/GaN light emitting layer, further comprising:
the pressure of the reaction cavity is kept at 300-400mbar, the temperature is kept at 700-750 ℃, and the flow rate is kept at 50 DEG000 NH of 70000sccm320-40sccm of TMGa, 1500-2000sccm of TMIn and 100-130L/min of N2Under the conditions of (1), In doped with In the range of 2.5 to 3.5nm is grownx1Ga(1-x1)An N layer, wherein x1 is 0.20-0.25, and the light-emitting wavelength is 450-455 nm;
raising the temperature to 750 plus 850 ℃, keeping the pressure of the reaction chamber at 300 plus 400mbar, and introducing NH with the flow rate of 50000 plus 70000sccm320-100sccm of TMGa and 100-130L/min of N2Growing a luminescent GaN layer of 8-15nm under the condition of (1); repeatedly and alternately growing Inx1Ga(1-x1)N layer and light-emitting GaN layer to obtain Inx1Ga（1-x1)N/GaN light emitting layer, Inx1Ga(1-x1)The number of the alternate growth cycles of the N layer and the light-emitting GaN layer is 7-15.
Further, wherein, growing the P-type AlGaN layer further comprises:
keeping the pressure of the reaction chamber at 200-400mbar and the temperature at 900-950 ℃, and introducing NH with the flow rate of 50000-70000sccm3TMGa 30-60sccm, H100-130L/min2100 TMAl with 130sccm, 1000 Cp with 1300sccm2Mg, continuously growing a P-type AlGaN layer with the thickness of 50-100nm, wherein the Al doping concentration is 1E20-3E20atom/cm3Mg doping concentration of 1E19-1E20atom/cm3。
Further, wherein, growing the P-type GaN layer doped with magnesium further comprises:
keeping the pressure of the reaction chamber at 400-900mbar and the temperature at 950-1000 ℃, and introducing NH with the flow rate of 50000-70000sccm320-100sccm of TMGa, 100-21000-Cp of 3000sccm2Mg, continuously growing a P-type GaN layer doped with magnesium with the thickness of 50-200nm, wherein the doping concentration of Mg is 1E19-1E20atom/cm3。
Further, wherein, cooling further comprises:
and (4) cooling to 650-.
Compared with the prior art, the method for epitaxial growth of the LED substrate based on the AlN template realizes the following beneficial effects:
(1) according to the method for epitaxial growth of the LED substrate based on the AlN template, the AlN template is sputtered on the LED substrate through the sputtering principle, the AlN template is used for replacing a low-temperature GaN layer of a traditional LED, the growth of high-temperature NGaN is only needed to be directly realized on the AlN template, the low-temperature GaN layer of the traditional LED and the low-temperature GaN layer are not needed to be corroded into an island shape, the epitaxial growth is simplified, and the production efficiency of the LED is improved.
(2) According to the method for epitaxial growth of the LED substrate based on the AlN template, the AlGaN layer and the nAlGaN layer grow on the AlN template, the transition from the AlN template to the N-type GaN layer is well solved, and the problems that the growth process for directly growing GaN on the AlN template is complex and the warping degrees of the grown U-type GaN and N-type GaN are great are solved.
(3) According to the method for epitaxial growth of the LED substrate based on the AlN template, the wavelength hit rate of the epitaxial wafer in the LED is improved, the crystal quality of the epitaxial wafer is improved, the crystal quality of the light-emitting layer is improved, the doping efficiency of the P-type GaN layer is improved, the mobility of the hole is improved, the wavelength hit rate is improved, the brightness and the light efficiency of the LED are improved, the hole mobility of the P-type GaN layer is improved, and the voltage is reduced; the improvement of the crystal quality enables reverse voltage to be increased and antistatic capability to be improved, and the light emitting efficiency of the LED is integrally improved.
Of course, it is not necessary for any product in which the present invention is practiced to achieve all of the above-described technical effects simultaneously.
Other features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, which proceeds with reference to the accompanying drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.
FIG. 1 is a schematic flow chart of a conventional epitaxial growth method for an LED substrate in the prior art;
FIG. 2 is a schematic structural diagram of a conventional LED fabricated by epitaxial growth of a substrate of a light emitting diode according to the prior art;
fig. 3 is a schematic flow chart of a method for epitaxial growth of an AlN template-based led substrate according to embodiment 1 of the present invention;
fig. 4 is a schematic structural diagram of an LED manufactured by the method for epitaxial growth of an AlN template-based light emitting diode substrate according to embodiment 1 of the present invention;
fig. 5 is a schematic flow chart of a method for epitaxial growth of an AlN template-based led substrate according to embodiment 2 of the present invention.
Detailed Description
Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.
The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.
Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.
In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.
Example 1
As shown in fig. 3, which is a schematic flow chart of the method for epitaxial growth of the AlN template-based light emitting diode substrate according to this embodiment, the method described in this embodiment solves the problems in the prior art that the method for manufacturing an LED causes a low wavelength hit rate of the manufactured epitaxial wafer, a light crystal quality of the epitaxial wafer, a poor crystal quality of the light emitting layer, a decrease in doping efficiency of the P layer, and a decrease in mobility of holes; the prepared LED has the problems of reduced brightness, reduced lighting effect, reduced reverse voltage, poor antistatic capability and the like.
In this example, MOCVD (metal organic chemical vapor deposition) was used to grow high-brightness GaN-based LED epitaxial wafers using high-purity H2Or high purity N2Or high purity H2And high purity N2The mixed gas of (2) is used as a carrier gas, high-purity NH3As the N source, metal organic sources of trimethyl gallium (TMGa) and triethyl gallium (TEGa) as gallium sources, trimethyl indium (TMIn) as indium sources, and Silane (SiH) as an N-type dopant4) Trimethylaluminum (TMAl) as the aluminum source and magnesium diclomelate (CP) as the P-type dopant2Mg), a sapphire substrate, and the reaction pressure is between 70mbar and 900mbar, and the method specifically comprises the following steps:
step 301, processing the sapphire substrate.
Step 302, growing AlxGa(1-x)An N layer, further:
the pressure of the reaction cavity is kept at 100-300mbar, the temperature is kept at 900-1000 ℃, and meanwhile, the flow rate is led in at 30000-40000sccNH of m3100-130L/min N2Growing 500-800nm Al under the conditions of TMGa 50-100sccm and TMAl 100-200sccmxGa（1-x)N layer (x is in the range of 0.10-0.15).
Step 303 of growing AlyGa(1-y)An N layer, further:
keeping the pressure of the reaction chamber at 100-3100-130L/min N2Growing 500-800nm Al under the conditions of 100-200sccm TMGa and 50-100sccm TMAlyGa（1-y)N layer (y value range: 0.05-0.10).
Step 304, growing SivAlzGa(1-z-v)An N layer, further:
keeping the pressure of the reaction chamber at 300-3100-130L/min H2200-300sccm TMGa, 50-100sccm TMAl and 5-10sccm SiH4Under the conditions of (1), 500-800nm Si is grownvAlzGa（1-z-v)N layer (z is 0.03-0.05; v is 0.005-0.01), and Si doping concentration is 5E17-5E18atom/cm3。
And 305, growing an N-type GaN layer doped with Si.
Step 306, growing Inx1Ga（1-x1)An N/GaN light-emitting layer, wherein x1 is 0.20-0.25.
And 307, growing a P-type AlGaN layer.
And 308, growing a magnesium-doped P-type GaN layer.
And 309, cooling.
In the manufacturing process of the LED, the growth process of directly growing the GaN layer on the AlN layer is very complex, the warping degree between the grown U-shaped GaN layer and the N-shaped GaN layer is also very large, the GaN layer with better quality can be grown only by very strict control, meanwhile, the wavelength hit rate is low, and large-scale mass production cannot be realized.
As shown in fig. 4, a schematic structural diagram of an LED prepared by using the method for epitaxial growth of an AlN template-based light emitting diode substrate according to this embodiment is shown, where the LED includes the following structure: substrate 401, AlxGa(1-x)N layer 402, AlyGa(1-y)N layer 403, SivAlzGa（1-z-v)N layer 404, Si-doped N-type GaN layer 405, Inx1Ga(1-x1)N/GaN light-emitting layer 406, P-type AlGaN layer 407, P-type GaN layer 408 doped with magnesium, ITO layer 409, SiO2A passivation layer 410, an N electrode 411, and a P electrode 412.
Example 2
As shown in fig. 3 to 5, fig. 5 is a schematic flow chart of a method for epitaxial growth of a light emitting diode substrate based on an AlN template according to this embodiment, and on the basis of embodiment 1, specific contents of an epitaxial layer of a light emitting diode grown entirely based on an AlN template are described. The method for epitaxial growth of the light emitting diode substrate based on the AlN template comprises the following steps:
step 501, processing the sapphire substrate: simultaneously introducing NH with the flow of 10000-20000sccm into the reaction cavity of the metal organic chemical vapor deposition system with the substrate3100-130L/min H2And raising the temperature to 900-1000 ℃, and processing the substrate for 300-600 s under the condition that the pressure of the reaction cavity is 100-200 mbar.
Step 502, growing AlxGa(1-x)An N layer, further:
the pressure of the reaction cavity is kept at 100-300mbar and the temperature is kept at900 ℃ and 1000 ℃, and NH with the flow rate of 30000 ℃ and 40000sccm is introduced at the same time3100-130L/min N2Growing 500-800nm Al under the conditions of TMGa 50-100sccm and TMAl 100-200sccmxGa(1-x)N layer (x is in the range of 0.10-0.15).
Step 503, growing AlyGa（1-y)An N layer, further:
keeping the pressure of the reaction chamber at 100-3100-130L/min N2Growing 500-800nm Al under the conditions of 100-200sccm TMGa and 50-100sccm TMAlyGa(1-y)N layer (y value range: 0.05-0.10).
Step 504 of growing SivAlzGa（1-z-v)An N layer, further:
keeping the pressure of the reaction chamber at 300-3100-130L/min H2200-300sccm TMGa, 50-100sccm TMAl and 5-10sccm SiH4Under the conditions of (1), 500-800nm Si is grownvAlzGa(1-z-v)N layer (z is 0.03-0.05; v is 0.005-0.01), and Si doping concentration is 5E17-5E18atom/cm3。
Step 505, keeping the pressure of the reaction chamber at 300-220-50sccm SiH4Continuously growing a first Si-doped N-type GaN layer of 3-4 μm with a Si doping concentration of 5E18-1E19atom/cm3。
Step 506, keeping the pressure of the reaction chamber at 300-3200-400sccm TMGa, 100-130L/min H22-10sccm SiH4Continuously growing a second Si-doped N-type GaN layer of 200-400nm, wherein the doping concentration of Si is 5E17-1E18atom/cm3。
Step 507, keeping the pressure of the reaction chamber at 300-320-40sccm of TMGa, 100-22-10sccm SiH4Continuously growing a third Si-doped N-type GaN layer with the Si doping concentration of 1E18-5E18atom/cm at 50-100nm3。
Step 508 of growing Inx1Ga（1-x1)An N/GaN light-emitting layer, wherein x1 is 0.20-0.25. The method comprises the following specific steps: keeping the pressure of the reaction chamber at 300-400mbar and the temperature at 700-750 ℃, and introducing NH with the flow rate of 50000-70000sccm320-40sccm of TMGa, 1500-2000sccm of TMIn and 100-130L/min of N2Under the conditions of (1), In doped with In the range of 2.5 to 3.5nm is grownx1Ga（1-x1）An N layer, wherein x1 is 0.20-0.25, and the light-emitting wavelength is 450-455 nm;
raising the temperature to 750 plus 850 ℃, keeping the pressure of the reaction chamber at 300 plus 400mbar, and introducing NH with the flow rate of 50000 plus 70000sccm320-100sccm of TMGa and 100-130L/min of N2Growing a luminescent GaN layer of 8-15nm under the condition of (1); repeatedly and alternately growing Inx1Ga(1-x1）N/GaN layer and light-emitting GaN layer to obtain Inx1Ga（1-x1）N/GaN/GaN light emitting layer, Inx1Ga（1-x1)The number of the alternate growth cycles of the N/GaN layer and the light-emitting GaN layer is 7-15.
Step 509, growing a P-type AlGaN layer: keeping the pressure of the reaction chamber at 200-400mbar and the temperature at 900-950 ℃, and introducing NH with the flow rate of 50000-70000sccm3TMGa 30-60sccm, H100-130L/min2100 TMAl with 130sccm, 1000 Cp with 1300sccm2Mg, continuously growing a P-type AlGaN layer with the thickness of 50-100nm, wherein the Al doping concentration is 1E20-3E20atom/cm3Mg doping concentration of 1E19-1E20atom/cm3。
Step 510, growing a magnesium-doped P-type GaN layer: keeping the pressure of the reaction chamber at 400-900mbar and the temperature at 950-1000 ℃, and introducing NH with the flow rate of 50000-70000sccm3T of 20-100sccmMGa, 100-130L/min H21000-Cp of 3000sccm2Mg, continuously growing a P-type GaN layer doped with magnesium with the thickness of 50-200nm, wherein the doping concentration of Mg is 1E19-1E20atom/cm3。
Step 511, cooling: and (4) cooling to 650-.
In the method for epitaxial growth of the light emitting diode substrate based on the AlN template according to the present embodiment, the AlGaN layer and the nAlGaN layer are grown on the AlN template, so that transition from the AlN template to the N-type GaN layer is well solved, and problems that a growth process for directly growing GaN on the AlN template is complicated and warping degrees of U-type GaN and N-type GaN obtained by growth are great are solved.
Example 3
In this example, an LED sample 1 was prepared according to the conventional LED growth method, and a sample 2 was prepared according to the LED growth method of the present invention; the parameters of the epitaxial growth method for samples 1 and 2 are shown in table 1. The sample 1 and the sample 2 were simultaneously placed in an XRD measurement device (X-ray Diffraction, also called X-ray diffractometer) to measure the GaN layer level value and the luminescence layer level value, as shown in table 3. Sample 1 and sample 2 were then coated with an ITO layer of about 150nm thickness under the same pre-process conditions; plating a Cr/Pt/Au electrode with the thickness of about 1500nm under the same condition; coating a protective layer SiO with a thickness of about 100nm under the same conditions2Then, the sample was ground and cut under the same conditions into 635 μm by 635 μm (25mil by 25mil) chip particles, and then 100 dies were picked from each of sample 1 and sample 2 at the same positions and packaged into a white LED under the same packaging process. The photoelectric properties of sample 1 and sample 2 were then tested using an integrating sphere at a drive current of 350mA, and the results are shown in table 2.
TABLE 1 comparative table of growth parameters for sample 1 and sample 2
TABLE 2 comparison of the Electrical parameters of the products of sample 1 and sample 2
TABLE 3 TABLE of measurement results of XRD parameters of epitaxial wafers of sample 1 and sample 2
According to the analysis of the test result list data, the following results can be obtained: the data obtained by the integrating sphere are analyzed and compared, and the test data in Table 3 show that the crystal quality of the N-type GaN is improved by the AlN template growth method, the crystal quality of the light emitting layer is improved, the luminous efficiency of the LED is improved from 125m/w to 145Lm/w, the voltage is reduced by about 0.1V, and other parameters are improved; the LED grown on the AlN template by the LED epitaxial growth method can be produced in large scale and obtain good LED products.
According to the embodiments, the method for epitaxial growth of the light emitting diode substrate based on the AlN template has the following beneficial effects:
(1) according to the method for epitaxial growth of the LED substrate based on the AlN template, the AlN template is sputtered on the LED substrate through the sputtering principle, the AlN template is used for replacing a low-temperature GaN layer of a traditional LED, the growth of high-temperature NGaN is only needed to be directly realized on the AlN template, the low-temperature GaN layer of the traditional LED and the low-temperature GaN layer are not needed to be corroded into an island shape, the epitaxial growth is simplified, and the production efficiency of the LED is improved.
(2) According to the method for epitaxial growth of the LED substrate based on the AlN template, the AlGaN layer and the nAlGaN layer grow on the AlN template, the transition from the AlN template to the N-type GaN layer is well solved, and the problems that the growth process for directly growing GaN on the AlN template is complex and the warping degrees of the grown U-type GaN and N-type GaN are great are solved.
(3) According to the method for epitaxial growth of the LED substrate based on the AlN template, the wavelength hit rate of the epitaxial wafer in the LED is improved, the crystal quality of the epitaxial wafer is improved, the crystal quality of the light-emitting layer is improved, the doping efficiency of the P-type GaN layer is improved, the mobility of the hole is improved, the wavelength hit rate is improved, the brightness and the light efficiency of the LED are improved, the hole mobility of the P-type GaN layer is improved, and the voltage is reduced; the improvement of the crystal quality enables reverse voltage to be increased and antistatic capability to be improved, and the light emitting efficiency of the LED is integrally improved.
As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, apparatus, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustrative purposes only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.
Claims (9)
1. A method for epitaxial growth of a light emitting diode substrate based on an AlN template is characterized by comprising the following steps: treating substrate and growing AlxGa(1-x)N layer, grown AlyGa(1-y)N layer, grown SivAlzGa(1-z-v)N layer, growing Si-doped N-type GaN layer, growing Inx1Ga(1-x1)An N/GaN light-emitting layer, wherein x1 is 0.20-0.25, a P-type AlGaN layer is grown, a P-type GaN layer doped with magnesium is grown, and the temperature is reduced and cooled; wherein,
growing AlxGa(1-x)N layer, further of：
Keeping the pressure of the reaction chamber at 100-3100-130L/min N2Growing 500-800nm Al under the conditions of TMGa 50-100sccm and TMAl 100-200sccmxGa(1-x)N layer, x value range: 0.10-0.15;
growing AlyGa(1-y)An N layer, further:
keeping the pressure of the reaction chamber at 100-3100-130L/min N2Growing 500-800nm Al under the conditions of 100-200sccm TMGa and 50-100sccm TMAlyGa(1-y)N layer, y value range: 0.05-0.10;
growing SivAlzGa(1-z-v)An N layer, further:
keeping the pressure of the reaction chamber at 300-3100-130L/min H2200-300sccm TMGa, 50-100sccm TMAl and 5-10sccm SiH4Under the conditions of (1), 500-800nm Si is grownvAlzGa(1-z-v)N layer, z value range: 0.03-0.05, wherein v has the following value range: 0.005-0.01, and the doping concentration of Si is 5E17-5E18atom/cm3；
Processing the substrate, further:
simultaneously introducing NH with the flow of 10000-20000sccm into the reaction cavity of the metal organic chemical vapor deposition system with the substrate3100-130L/min H2And raising the temperature to 900-1000 ℃, and processing the substrate under the condition that the pressure of the reaction cavity is 100-200 mbar.
2. The method for epitaxial growth of the AlN template-based light emitting diode substrate according to claim 1, wherein the Si-doped N-type GaN layer is grown, further: NH3, TMGa and H are introduced2And SiH4And continuously growing the N-type GaN layer doped with Si.
3. The method for epitaxial growth of the AlN template-based light emitting diode substrate according to claim 2, wherein the Si-doped N-type GaN layer is grown, further:
keeping the pressure of the reaction chamber at 300-220-50sccm SiH4Continuously growing a Si-doped N-type GaN layer of 3-4 μm with a Si doping concentration of 5E18-1E19atom/cm3。
4. The method for epitaxial growth of the AlN template-based light emitting diode substrate according to claim 3, wherein the Si-doped N-type GaN layer is grown, further:
keeping the pressure of the reaction chamber at 300-220-50sccm SiH4Continuously growing a first Si-doped N-type GaN layer of 3-4 μm with a Si doping concentration of 5E18-1E19atom/cm3；
Keeping the pressure of the reaction chamber at 300-3200-400sccm TMGa, 100-130L/min H22-10sccm SiH4Continuously growing a second Si-doped N-type GaN layer of 200-400nm, wherein the doping concentration of Si is 5E17-1E18atom/cm3。
5. The method for epitaxial growth of the substrate of the light emitting diode based on the AlN template, according to claim 4, wherein the Si-doped N-type GaN layer is grown, further comprising:
keeping the pressure of the reaction chamber at 300-220-50sccm SiH4Continuously growing a first Si-doped N-type GaN layer of 3-4 μm with a Si doping concentration of 5E18-1E19atom/cm3；
The pressure of the reaction cavity is kept at 300-600-mbar, temperature of 1000-1200 ℃ and NH with flow rate of 30000-60000sccm3200-400sccm TMGa, 100-130L/min H22-10sccm SiH4Continuously growing a second Si-doped N-type GaN layer of 200-400nm, wherein the doping concentration of Si is 5E17-1E18atom/cm3；
Keeping the pressure of the reaction chamber at 300-320-40sccm of TMGa, 100-22-10sccm SiH4Continuously growing a third Si-doped N-type GaN layer with the Si doping concentration of 1E18-5E18atom/cm at 50-100nm3。
6. The method of claim 1, wherein In is grown by growing the substrate epitaxially on the AlN template-based light emitting diodex1Ga(1-x1)An N/GaN light emitting layer, further comprising:
keeping the pressure of the reaction chamber at 300-400mbar and the temperature at 700-750 ℃, and introducing NH with the flow rate of 50000-70000sccm320-40sccm of TMGa, 1500-2000sccm of TMIn and 100-130L/min of N2Under the conditions of (1), In doped with In the range of 2.5 to 3.5nm is grownx1Ga(1-x1)An N layer, wherein x1 is 0.20-0.25, and the light-emitting wavelength is 450-455 nm;
raising the temperature to 750 plus 850 ℃, keeping the pressure of the reaction chamber at 300 plus 400mbar, and introducing NH with the flow rate of 50000 plus 70000sccm320-100sccm of TMGa and 100-130L/min of N2Growing a luminescent GaN layer of 8-15nm under the condition of (1); repeatedly and alternately growing Inx1Ga(1-x1)N layer and light-emitting GaN layer to obtain Inx1Ga(1-x1)N/GaN light emitting layer, Inx1Ga(1-x1)The number of the alternate growth cycles of the N layer and the light emitting GaN layer is 7-15.
7. The method of claim 1, wherein the P-type AlGaN layer is grown by further comprising:
the pressure of the reaction cavity is kept at 400mbar, the temperature is kept at 950 ℃ and the flow rate is kept at 700 ℃ and 50000-NH of 00sccm3TMGa 30-60sccm, H100-130L/min2100 TMAl with 130sccm, 1000 Cp with 1300sccm2Mg, continuously growing a P-type AlGaN layer with the thickness of 50-100nm, wherein the Al doping concentration is 1E20-3E20atom/cm3Mg doping concentration of 1E19-1E20atom/cm3。
8. The method of claim 1, wherein the growing of the Mg-doped P-type GaN layer further comprises:
keeping the pressure of the reaction chamber at 400-900mbar and the temperature at 950-1000 ℃, and introducing NH with the flow rate of 50000-70000sccm320-100sccm of TMGa, 100-21000-Cp of 3000sccm2Mg, continuously growing a P-type GaN layer doped with magnesium with the thickness of 50-200nm, wherein the doping concentration of Mg is 1E19-1E20atom/cm3。
9. The method for epitaxial growth of the AlN template-based led substrate according to claim 1, wherein the cooling further comprises:
and (4) cooling to 650-.
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